Gripper stirrup for a can filling machine



April 12, 1966 H. BURGERT, JR 3,245,436

GRIPPER STIRRUP FOR A CAN FILLING MACHINE I Filed Nov. 13, 1963 3Sheets-Sheet 1 TYPE. 2-

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ATTORNEY April 1966 H. BURGERT, JR 3,245,436

GRIPPER STIRRUP FOR A CAN FILLING MACHINE Filed NOV. 13, 1963 5Sheets-Sheet 2 A TTORNE Y April 12, 1966 H. BURGERT, JR

GRIPPER STIRRUP FOR A CAN FILLING MACHINE 3 Sheets-Sheet Z5 Filed Nov.15, 1963 H m M v 0 N GW W United States Patent 3,245,436 GRIPPER STIRRUPFOR A CAN FILLING MACHINE Henry Burgert, Jr., Cleveland, Ohio, assignorto Aluminum Company of America, Pittsburgh, Pa., a corporation ofPennsylvania Filed Nov. 13, 1963, Ser. No. 323,439 4 Claims. (Cl.bib-165) This invention relates to a filling machine of the type adaptedfor filling flat top cans with carbonated beverages such as beer and,more particularly, to the can lifting stirrups or platforms of thefiller by which the cans are handled to and from the filling headsthereof.

In canning beer, for example, it is highly desirable to employ eitherthe customary steel cans of conventional construction or seamlessaluminum cans produced by impact-extrusion with an integral bottom andside wall and hence having no bottom seam head or chime as do the steelcans. With the steel cans, the lower bead, interengaged with ashouldered back-stop on the can lifting stirrups of the filler, is usedto pull the cans from the filling heads following the filling theoperation in the event of sticking of the cans in theheads. However,this expedient is not feasible with the seamless aluminum cans sincethey have no lower head or chime.

The present invention, therefore, aims to provide a can filling machinewith can lifting stirrups which will adapt the machine to accept forfilling with equal facility the customary steel cans and seamlessaluminum cans and which will be effective to withdraw the cans from thefiller heads when the stirrups are lowered to their can discharge level.

Another object is to provide a can filling machine with stirrups whichwill easily receive and effectively grip seamless aluminum cans withoutcrushing or denting the fragile side wall thereof, which will hold themaccurately centered'with respect to the filling heads or spouts andwhich will assure withdrawal of the cans from the filler heads despitethe tendency of the cans to adhere to the sealing rings thereof.

A further object is to provide a can gripping stirrup for a can fillingmachine, including a gripping member so shaped as to provide anincreased frictional grip on a seamless aluminum can in response torelative vertical movement between the can and the stirrup when thestirrup starts down subsequent to the can filling operation, whereby toassure that the can will move down with the stirrup.

Other objects and advantages of the invention will be apparent from aconsideration of the following specification and accompanying drawings.

In the drawings:

FIG..1 is a plan view of a rotary can filling machine with thesuperstructure of the rotary table and most of the circular series ofthe can lifting platforms or stirrups omitted;

FIG. 2 is a vertical cross-section, on an enlarged scale, taken on theline II-II of FIG. 1, showing a can positioned on a stirrup as deliveredthereto by the infeed star wheel;

FIG. 3 is a substantially full scale top plan view of a single stirrupprovided with the can gripping elements of the invention;

FIG. 4 is a front elevational view of the stirrup of FIG. 3;

FIG. 5 is a side elevational view thereof;

FIG. 6 is a cross-sectional detail view, taken on the line VL-VI of FIG.3, showing on an enlarged scale one of the can gn'pping rollers and itsmounting on the stirrup;

3,245,436 Patented Apr. 12, 1966 FIG. 7 is a top plan view of the detailshown in FIG. 6;

FIG. 8 is a top plan view similar to FIG. 3, but showing the stirrupprovided with a modified form of can gripping elements;

FIG. 9 is a front elevational view of the stirrup shown in FIG. 8;

FIG. 10 is a cross-sectional detail view on an enlarged scale taken online X-X of FIG. 8, showing the, can gripping element in its free state;

FIG. 11 is a detail view similar to FIG. 10, but showingi the grippingelement engaged with the can side wall, an

FIG. 12 is a detail view on an enlarged scale taken on line XII-XII ofFIG. 8.

Referring to the drawings, FIGS. 1 and 2 illustrate a rotary filler ofthe counter-pressure type commonly used in the brewing industry forfilling open top cans. The filler includes a circular table 10 which isrotatably mounted on a vertical column (not shown) and a closed tank orbowl 11 which is supported above the table and rotates therewith. Thetable is provided around its rim with the usual circular series ofclosely spaced vertical lifting cylinder 12. The bowl 11 is providedwith a like circular series of filler heads or spouts 14 depending fromthe bottom thereof, each head being coaxial with a lifting cylindertherebelow. These filling heads may be of the.

general type disclosed in George L. N. Meyer Patent No. 3,067,785,issued December 11, 1962, for Can Filling Head.

Each cylinder 12 has a piston (not shown) and a square piston rod 15, onthe upper end of which a canreceiving pad or stirrup 16 is secured,there being minimal clearance between the stirrups.

Empty cans enter the filler on a conveyor 17 and are spaced by screw 18to enter the pockets of intake star wheel 19 which moves them along aguide plate 20 and onto successive stirrups 16. Each stirrup has aroller 21 s which is cooperable with a cam 22 so that the stirrup willbe in its lower can intake and dischargelevel, as shown in FIG. 2, toreceive the can from the infeed star wheel at the level of fixed table23, the cans being removed from the stirrups at this level by the guideplate 20 and a discharge star wheel 24.

After leaving the intake star, air pressure in the lifting cylinderupwardly actuates the piston and its rod to elevate the stirrup and thusraise the empty can thereon into sealing engagement with sealing ring 25of the filling head 14. The valves of the filling head will then beoperated and the can filled with beverage from bowl 11 in a manner wellknown in the art.

With filling complete, the stirrup is moved by coaction of its roller 21with cam 22 down to its lower level so as to release the can from thefilling head. However, the can tends to stick to the sealing ring 25 andthus hang up in the head 14 when it should move down with the stirrup.It is at this point in the operation of the filler that the presentinvention functions in connection with seamless aluminum cans to effectcan withdrawal from the filling heads and thus prevent mechanicaljamming and malfunction of the filler.

A stirrup embodying one form of the invention is shown in FIGS. 3through 7. Upstanding from the top of the stirrup around its peripheryis a rigid U-shaped collar 26 which opens or faces outwardly withrespect to the rotary path of the stirrup and forms a semi-circularpocket to receive a can from the intake star wheel 19. The circularinner wall 27 of the collar is concentric to the vertical axis of thestirrup and is undercut totprovide a bottomv 'are being run through thefiller. A wear plate usually provided on the top of the stirrup is shownat 29.

The collar is provided with diametrical recesses or window openingsthrough its ends. A small roller 31 of soft rubber, such as urethane atabout 40 durometer hardness, is rotatably retained in each window by avertical pin 32. The roller is necessarily of small diameter so as toremain within the clearance line between stirrups. The vertical pin 32is supported at both ends so as to be firmly held against bending ortilting out of vertical position despite its slimness. The lower end ofthe pin fits in a bore in the top of the stirrup and it has screwthreaded engagement at its upper end with the top portion of the collar(best seen in FIG. 6) to retain it assembled to the stirrup and permitworn or damaged rollers to be readily replaced. It will also be seenthat the roller is held by its bottom engagement with the lower windowwall in elevated position with respect to the top plane of wear plate 29and that the roller is of inverted conical form at its lower end. Thisprovides head or chime clearance when cans with a bottom chime are beingrun through the filler.

The rollers 31 are spaced apart to have interference fit with the sidewall of a can so as to cause slight roller compression by the canentered in the pocket of collar 26 whereby the rollers frictionallyengage and exert a slight radial pressure against the can adjacent tothe lower end thereof, but insufiicient to permanently dent the fragilecan side wall. In the vertical direction, however, sufiicient frictionforce is developed in this manner to keep the seamless aluminum can C inplace, or held down to the stirrup, during the down stroke of thestirrup to pull the can down from the filler head. The rollers,therefore, constitute lightly loaded friction grippers relying onfriction to hold the can, rather than high pressure grippers 'asheretofore used for rigid bottles.

When the can C is pushed into the collar pocket of the stirrup by theintake star wheel, the rollers 31 preferably engage the can slightlyforwardly of the can diameter, with the back side of the can inengagement with the mid-point X of the collar. Thereby, the rollersexert a slight component of force on the can which tends to retain thecan against accidental lateral displacement out of the collar pocket ofthe stirrup. As received and frictionally held on the stirrup, the canis substantially centered under the filling head 14.

The use of frictional can grippers of the above-described roller type ispreferred, since they normally will rotate on the pins 32 by the in andout movement of the cans and thus distribute wear around the rollerperipheries. However, fixed grippers may be used, as shown in FIGS. 8, 9and 10. Here, the stirrup has a rigid U-shaped collar 33 fastened byscrews 34 to the top of the stirrup to form a can-receiving pocket. Itscircular inner wall 35 is undercut to provide a bottom chime-receivingrecess or groove 36 therein. Wall 35 also is vertically recessed at itsdiametrically opposite ends and midway therebetween. These inwardlyfacing recesses 37 are joined by an inwardly open dovetail groove 38 inwall 35 located above the chime groove 36. Suitably, as by casting, softrubher, such as urethane at about 3540 durometer hardness, is providedin the recesses 37 and their joining groove, whereby the collar isprovided with the three inwardly facing grippers 40. The grippers arerecessed in continuation of groove 36 in the collar and are formed witha plurality of vertically spaced, flexible ribs or fingers 41 acrosstheir circular inner face. The two opposed grippers are spaced apart tohave interference fit at their inner faces with a can side wall. As bestseen in FIG. 10, the fingers only extend part way through the thicknessof the grippers, and have a flat bottom and increase in verticalthickness from the free inner tip to the outer base thereof. Due to theflexibility and shape of the fingers 41, they provide an increasedfrictional grip on a seamless aluminum can during the down stroke of thestirrup.

As such a can moves onto the stirrup, the fingers 41 of thediametrically opposed grippers 46) are slightly compressed and bent ordeflected downwardly by the can, as illustrated in FIG. 11. Thesegrippers frictionally hold the can in the stirrup pocket in contact withthe back gripper in a position substantially centered under the fillinghead. The back gripper serves to provide additional friction force onthe can, its fingers 41 being compressed by the centered can. When canfilling is completed and the stirrup starts down, if the can sticks tothe sealing ring 25, the resultant relative movement between thegrippers and the can will cause the fingers 41 to pivot about their baseand push into the side wall of the can. The result is a tighterfrictional grip on the can sufficient to force the can to withdraw fromthe filler head.

if desired, the roller form of gripping members shown in F165. 3 and 6may be formed with flexible rib or finger formations around theperiphery thereof to provide a self-tightening friction grip on thechimeless-bottom can. It will also be apparent that minor variation fromthe forms of the invention herein disclosed may be made withoutdeparting from the invention as defined in the appended claims.

What is claimed is:

1. In a rotary counter-pressure can filling machine having a verticallyreciprocable can lifting stirrup cooperable with a can filling head,said stirrup adapted for handling seamless aluminum cans into and out ofsealing engagement with said filling head and comprising,

(a) a rigid U-shaped collar upstanding from the top of the stirrup aboutthe periphery thereof and forming a semi-circular can-receiving pocketthereon, centered below said filling head,

(b) said collar having diametrical inwardly facing recesses at its ends,

(c) a pair of soft rubber grippers of between about 35 to 40 durometerhardness individually secured in said recesses,

(d) said grippers being spaced apart to have interference fit at theirinner faces with a can entered in said pocket so as to be slightlycompressed by the can and frictionally engage the same,

(e) the compressed grippers developing sufiicient friction force on saidcan in the vertical direction to withdraw the can from said filling headwhen said stirrup is moved downwardly from said head.

2. In a rotary counter-pressure can filling machine having a verticallyreciprocable can lifting stirrup cooperable with a can filling head,said stirrup adapted for handling seamless aluminum cans into and out ofsealing engagement with said filling head and comprising,

(a) a rigid U-shaped collar upstanding from the top of the stirrup aboutthe periphery thereof and forming a semi-circular can-receiving pocketthereon, centenered below said filling head,

(b) said collar having diametrical inwardly facing recesses at its ends,

(c) a pair of soft rubber grippers of between about 35 to 40 durometerhardness individually secured in said recesses,

(d) each said gripper having a plurality of vertically spaced flexiblefingers extending across its inner canengaging face,

(e) each finger having a fiat bottom and a vertical thickness whichincreases from its free inner tip to the outer base thereof,

(f) said grippers being spaced apart to have interference fit at thetips of said fingers with the side wall of a can entered in said pocketwhereby said fingers are slightly compressed and downwardly deflected bysaid can and frictionally engage the same,

(g) said gripper fingers operable to pivot about their base and increasetheir frictional grip on said can responsively to relative verticalmovement between said stirrup and said can when said stirrup is moveddownwardly from said filling head, whereby said can is forced towithdraw from said head.

3. The stirrup structure as defined in claim 2 wherein said collar andsaid grippers have a bead recess extending throughout the annular extentthereof adjacent to the can supporting top of said stirrup and adaptedto receive the lower bead of a steel can, whereby the filling machine isadapted to accept for filling fiat top cans with and without a bottomchime Wih equal facility.

4. In a rotary counter-pressure can filling machine having a verticallyreciprocable can lifting stirrup cooperable with a can filling head,said stirrup adapted for handling seamless aluminum cans into and out ofsealing engagement with said filling head and comprising,

(a) a rigid U-shaped collar upstanding from the top of the stirrup aboutthe periphery thereof and forming a semi-circular can-receiving pocketthereon, centered below said filling head,

(b) said collar having diametrical window openings through its ends anda bead-receiving recess extending throughout the annular extent thereofadjacent the tops of said stirrup,

(c) a soft rubber roller of between about 3540 durometer hardnessrotatably mounted in each of said windows on a vertical pin supportinglyengaged at both ends against tilting out of vertical position,

(d) said rollers spaced apart to have interference fit with a seamlesscan be entered in said pocket and be slightly radially compressed by thecan and frictionally engage the same, whereby they develop sufiicientfriction force on said can in the vertical direction to withdraw the canfrom said filling head when said stirrup is moved down from said head,

(e) said rollers engaging said can forwardly of the diameter of the canand thereby retaining the can in said pocket substantially centeredunder said filling head as initially received on said stirrup, and

(f) said rollers being supported above the top cansupporting plane ofsaid stirrup and being shaped at their lower ends to provide beadclearance, so that cans with a bottom seam bead may be run through thefilling machine without roller damage.

References Cited by the Examiner UNITED STATES PATENTS 2,650,012 8/1953Kummer et a1. 141-172 X 3,172,434 3/1965 Bou-cher 141172 X 3,179,2374/1965 Ninneman 53367 25 LAVERNE D. GEIGER, Primary Examiner.

1. IN A ROTARY COUNTER-PRESSURE CAN FILLING MACHINE HAVING A VERTICALLYRECIPROCABLE CAN LIFTING STIRRUP COOPERABLE WITH A CAN FILLING HEAD,SAID STIRRUP ADAPTED FOR HANDLING SEAMLESS ALUMINUM CANS INTO AND OUT OFSEALING ENGAGEMENT WITH SAID FILLING HEAD AND COMPRISING, (A) A RIGIDU-SHAPED COLLAR UPSTANDING FROM THE TOP OF THE STIRRUP ABOUT THEPERIPHERY THEREOF AND FORMING A SEMI-CIRCULAR CAN-RECEIVING POCKETTHEREON, CENTERED BELOW SAID FILLING HEAD, (B) SAID COLLAR HAVINGDIAMETERICAL INWARDLY FACING RECESSES AT ITS ENDS, (C) A PAIR OF SOFTRUBBER GRIPPERS OF BETWEEN ABOUT 35 TO 40 DUROMETER HARDNESSINDIVIDUALLY SECURED IN SAID RECESSES, (D) SAID GRIPPERS BEING SPACEDAPART TO HAVE INTERFERENCE FIT AT THEIR INNER FACES WHT A CAN ENTERED INSAID POCKET SO AS TO BE SLIGHTLY COMPRESSED BY THE CAN AND FRICTIONALLYENGAGE THE SAME, (E) THE COMPRESSED GRIPPERS DEVELOPING SUFFICIENTFRICTION FORCE ON SAID CAN IN THE VERTICAL DIRECTION TO WITHDRAW THE CANFROM SAID FILLING HEAD WHEN SAID STIRRUP IS MOVED DOWNWARDLY FROM SAIDHEAD.